New features

  • md_pattern() has an additional argument sort_columns to provide the option to switch off the sorting of columns by number of missing values.
  • sum_duration(): new function to get sum of computational time across chains, phases, runs, …

Bug fixes

  • formula() now also return the model formula when add_samples() is used.
  • JM_imp() with ordinal longitudinal outcome is not using the correct version of the linear predictor in the quadrature procedure approximating the integral in the survival.
  • Bug causing the wrong elements of the data matrix to be monitored when monitor_params(imps = TRUE) in survival models fixed.
  • predDF(): bugfix for models including auxiliary variables (which were previously not included into the data)
  • nonprop: bugfix for non-proportional effects in covariate models

Small improvements

  • Use of add_samples() will now result in the call element of a JointAI object being a list and no longer a nested list.
  • Re-structuring of the JAGS model code for proportional hazards models to reduce computational time.
  • change in how parallel computation is done: does not rely on doFuture and foreach any more, only package future is required.
  • comp_info element of fitted JointAI object has changed due to the changes in parallel computing, and computational time is not reported separately for the adaptive phase and the sampling phase, and separately per chain when parallel computation was used.
  • predict() is now a lot faster for proportional hazards models.

New features

  • custom: new argument in the main analysis functions that allows the user to replace the JAGS syntax for sub-models with custom syntax. The argument expects a named list where the names are the names of the variables for which the custom model will be used. This feature requires some knowledge of JAGS syntax.
  • append_data_list: new argument in the main analysis functions that allows the user to add elements to the list of data that is passed to JAGS. This may be necessary for custom sub-models.
  • rd_vcov: new argument in the main analysis functions that allows the specification of the structure of the random effects variance-covariance matrices in (multivariate) mixed models (and joint models).

Minor improvements and bug fixes

  • Bug fix in re-scaling of random effects variance covariance matrix in multi-level models with >2 levels where some levels have only random intercept.
  • Bug fix in generating the names of random effect nodes to monitor when there are multiple analysis models and some do not have random effects.
  • Bug fix in plot_all() not displaying the variable name in the message shown for character string variables.
  • Bug fix in set_refcat(): wasn’t displaying the factor labels correctly
  • print.JointAI: bugfix for multivariate mixed models with full variance-covariance matrix of the random effects that had the same number of random effects for each outcome, for which the printing of this matrix resulted in an error.
  • Bug fix: when using a function of a variable as auxiliary this is now (again) correctly used as covariate in the linear predictor of covariate models (bug was introduced in commit 15014dcd)

New features

  • rd_vcov(): new function added to extract the random effect variance- covariance matrices (posterior means)

Minor improvements and bug fixes

  • change in the way the model formula is contained in the model call, which should make it possible to call *_imp() functions from within another function that has the model formula as an argument.
  • fixed issue that resulted in an error when the data was previously attached to the search path

Minor improvements and bug fixes

  • data_list: omit data matrix M_* from data_list if ncol == 0
  • data_list: syntax to checking which pos_* to include can handle the case with multiple grouping variables being on the same, lowest level; before pos_* was excluded for only one of them
  • random effects: it is now possible to use different grouping levels in different sub-models (when providing a list of model formulas)
  • add_samples(): remove unnecessary call to doFuture::registerDoFuture()
  • predDF() bug fix: the parameter for all methods is now called object
  • list_models() now also works for errored JointAI objects
  • Bug fix for models with an interaction between a repeatedly measured variable and a random slope variable. (The term was wrongly written in the mean structure for the random effect instead of the main linear predictor.)

This version of JointAI contains some major changes. To extend the package it was necessary to change the internal structure and it was not possible to assure backward compatibility.

New features

New analysis model types

Hierarchical models with multiple levels of grouping

It is now possible to fit hierarchical models with more than one level of grouping, with nested as well as crossed random effects (check the help file) of the main model function for details on how to specify such random effects structures.

This does also apply to survival models, i.e., it is possible to specify a random effects structure to model survival outcomes in data with a hierarchical structure, e.g., in a multi-centre setting.

Proportional hazards model with time-dependent covariates

coxph_imp() can now handle time-dependent covariates using last-observation-carried-forward. This requires to add (1 | <id variable>) to the model formula to identify which rows belong to the same subject, and to specify the argument timevar to identify the variable that contains the observation time of the longitudinal measurements.

Multivariate models

By providing a list of model formulas it is possible to fit multiple analysis models (of different types) simultaneously. The models can share covariates and it is possible to have the response of one model as covariate in another model (in a sequential manner, however, not circular).

Partial proportional odds models for ordinal responses

As before, proportional odds are assumed by default for all covariates of a cumulative logit model. The argument nonprop accepts a one-sided formula or a named list of one-sided formulas in which the covariates are specified for which non-proportional odds should be assumed.

Additionally, the argument rev is available to specify a vector of names of ordinal responses for which the odds should be inverted. For details, see the the help file.

Other new features

  • The functions lmer_imp() and glmer_imp() are aliases for lme_imp() and glme_imp().
  • All mixed models can be specified using the nlme type specification (using fixed and random) as well as using specification as in lme4 (with a combined model formula for fixed and random effects).
  • The argument df_basehaz in coxph_imp() and JM_imp() allows setting the number of degrees of freedom in the B-spline basis used to model the baseline hazard.
  • The global setting options("contrasts") is no longer ignored. For completely observed covariates, any of the contrasts available in base R are possible and options("contrasts") is used to determine which contrasts to use. For covariates with missing values, effect coding (contr.sum) and dummy coding (contr.treatment) are possible. This means that for completely observed ordered factors the default is contr.poly, but for incomplete ordered factors the default is contr.treatment.

Other changes

  • Within summary(), the argument multivariate to the function GR_crit() is now set to FALSE to avoid issues. The multivariate version can still be obtained by using GR_crit() directly.
  • The parameters of the baseline hazard for coxph_imp() and JM_imp() are monitored automatically when “analysis_main = TRUE”.
  • The function get_models() is no longer exported because it now requires more input variables and is no longer convenient to use. To obtain the default specification of the model types use one of the main functions (*_imp()), set n.adapt = 0 (and n.iter = 0), and obtain the model types as <mymodel>$models.
  • list_models() now returns information on all sub-models, including the main analysis models (previously it included only information on covariates).
  • The output of parameters() has changed. The function returns a list of matrices, one per analysis model, with information on the response variable, response category, name of the regression coefficient and its associated covariate.
  • The argument missinfo = TRUE in summar() adds information on the missing values in the data involved in a JointAI model (number and proportion of complete cases, number and proportion of missing values per variable).
  • The argument ridge has changed to shrinkage. If shrinkage = "ridge", a ridge prior is used for all regression coefficients in all sub-models. If a vector of response variable names is provided to shinkage, ridge priors are only used for the coefficients in these models.
  • default_hyperpars(): The default hyper-parameters for random effects are no longer provided as a function but more consistently with the hyper-parameters for other model parts, as a vector (within the list of all hyper-parameters).
  • default_hyperpars(): the default number of degrees of freedom in the Wishart distribution used for the inverse of the random effects covariance matrix is now the number of random effects + 1 (was the number of random effects before).
  • The effect of using a seed in JointAI is now only local, i.e., in functions in which set.seed() is called, the random number generator state .Random.seed before setting the seed is recorded, and re-set to that value on exiting the function.
  • In predDF() the argument var has changed to vars and expects a formula. This extends the functionality of predDF() to let multiple variables vary.
  • Some of the elements of a JointAI object have changed. Potentially relevant for users:
    • JointAI objects now contain information on the computational time and environment they were run in: the element comp_info contains the time-stamp the model was fitted, the duration of the computation, the JointAI version number and the R session info.
    • The JAGS model is stored as character string in the element jagsmodel.
  • The arguments warn and mess now also affect the output of rjags.
  • The doFuture package is used for parallel computation instead of doParallel. Parallel computation is specified by setting a future::plan() for how the “future” should be handled. As a consequence, the arguments parallel and n.cores are no longer used. Information on the setting that was used with regards to parallel computation is returned in a JointAI object via comp_list$future.

Bug fixes

  • Scaling of continuous covariates is no longer done in the data, but in the JAGS model. This fixes the issue that previously the estimated variance parameters of continuous covariates and variance parameters of their random effects were incorrect (this issue only affected the covariate models, not the main analysis model).

Bug fixes

  • Fixed bug that messed up coefficients in clmm covariate model when there are no baseline covariates in the model
  • enable newdata for predict() that does not contain the outcome variable
  • add_samples(): calculation of end() of MCMC samples fixed

Bug fixes

  • bug in add_samples() when used in parallel with thinning fixed
  • bug fixed that occurred when a complete longitudinal categorical variable was used in a model that did not contain any incomplete baseline variables
  • bug-fix for monitoring random effects
  • fixed typo in selecting parameters in Gamma models
  • predict() can now handle newdata with missing outcome values; predicted values for cases with missing covariates are NA (prediction with incomplete covariates is planned to be implemented in the future)
  • bug-fix for get_MIdat() and plot_imp_distr() when only one variable has missing values
  • bug-fix for longitudinal model with interaction with random slope variable
  • bug-fix for model with multiple longitudinal ordinal incomplete covariates (fixed wrong selection of columns of the design matrix of longitudinal covariates in these models)

Minor changes

  • moved message about bug reports to startup
  • enabled inverse link by adding max restriction
  • “:” in factor labels are automatically replaced by "_"
  • argument ncores has changed to n.cores for consistency with n.iter, n.chains, etc.
  • coxph_imp() does no longer use a counting process implementation but uses the likelihood in JAGS directly via the zeros trick

New Features / Extensions

  • predict() now has an argument length to change number of evaluation points
  • summary(), predict(), traceplot(), densplot(), GR_crit(), MC_error() now have an argument exclude_chains that allows to specify chains that should be omitted
  • citation() now refers to a manuscript on arXiv
  • glmm_lognorm available to impute level-1 covariates with a log-normal mixed model
  • methods residuals() and plot() available for (some of the) main analysis types (details see documentation)
  • argument models added to get_models() so that the user can specify to also include models for complete covariates (which are then positioned in the sequence of models according to the systematic used in JointAI). Specification of a model not needed for imputation prints a notification.
  • JointAI objects (most types) now also include residuals and fitted values (so far, only using fixed effects)

Bug fixes

  • Error message in print.JointAI fixed

Bug fixes

  • bug in ordinal models with only completely observed variables fixed (all necessary data is not passed to JAGS)
  • enable thinning when using parallel sampling
  • matrix Xl is no longer included in data_list when it is not used in the model
  • bug-fix in subset when specified as vector
  • bug-fix in ridge regression (gave an error message)
  • bug-fix in recognition of binary factors that are coded as numeric and have missing values
  • bug-fix in summary: range of iterations is printed correctly now when argument end is used
  • bug-fix: error that occurred in re-scaling when reference category was changed is solved
  • bug-fix in survival models: coding of censoring variable fixed

Minor changes

  • summary() calls GR_crit() with argument autoburnin = FALSE unless specified otherwise via ...
  • when inits is specified as a function, the function is evaluated and the resulting list passed to JAGS (previously the function was passed to JAGS)
  • the example data simong and simWide have changed (more variables, less subjects)
  • added check if there are incomplete covariates before setting imp_pars = TRUE (when user specified via monitor_params or subset)
  • in survreg_imp the sign of the regression coefficient is now opposite to match the one from survreg

Important

  • the argument meth has changed to models

Bug fixes

  • add_samples(): bug that copied the last chain to all other chains fixed
  • bug-fix for the order of columns in the matrix Xc, so that specification of functions of covariates in auxiliary variables works better
  • adding vertical lines to a densplot() issue (all plots showed all lines) fixed
  • nested functions involving powers made possible
  • typo causing issue in poisson glm and glme removed

Minor changes

  • plot_all(), densplot(), and traceplot() limit the number of plots on one page to 64 when rows and columns of the layout are not user specified (to avoid the ‘figure margins too large’ error)
  • change in longDF example data: new version containing complete and incomplete categorical longitudinal variables (and variable names L1 and L2 changed to c1 and c2)
  • Some minor changes in notes, warnings and error messages
  • The function list_impmodels() changed to list_models() (but list_impmodels() is kept as an alias for now)
  • improved handling of functional forms of covariates (also in longitudinal covariates and random effects)

New Features / Extensions

  • clm_imp() and clmm_imp(): new functions for analysis of ordinal (mixed) models
  • It is now possible to impute incomplete longitudinal covariates (continuous, binary and ordered factors).
  • coxph_imp(): new function to fit Cox proportional hazards models with incomplete (baseline) covariates
  • Argument no_model allows to specify names of completely observed variables for which no model should be specified (e.g., “time” in a mixed model)
  • Shrinkage: argument ridge = TRUE allows to use shrinkage priors on the precision of the regression coefficients in the analysis model
  • plot_all() can now handle variables from classes Date and POSIXt
  • new argument parallel allows different MCMC chains to be sampled in parallel
  • new argument ncores allows to specify the maximum number of cores to be used
  • new argument seed added for reproducible results; also a sampler (.RNG.name) and seed value for the sampler (.RNG.seed) are set or added to user-provided initial values (necessary for parallel sampling and reproducibility of results)
  • plot_imp_distr(): new function to plot distribution of observed and imputed values

Bug fixes

  • RinvD is no longer selected to be monitored in random intercept model (RinvD is not used in such a model)
  • fixed various bugs for models in which only the intercept is used (no covariates)

Minor changes

  • summary(): reduced default number of digits
  • continuous variables with two distinct values are converted to factor
  • argument meth now uses default values if only specified for subset of incomplete variables
  • get_MIdat(): argument minspace added to ensure spacing of iterations selected as imputations
  • densplot(): accepts additional options, e.g., lwd, col, …
  • list_models() replaces the function list_impmodels() (which is now an alias)

Extensions

  • coef() method added for JointAI object and summary.JointAI object
  • confint() method added for JointAI object
  • print() method added for JointAI object
  • survreg_imp() added to perform analysis of parametric (Weibull) survival models
  • glme_imp() added to perform generalized linear mixed modelling
  • extended documentation; two new vignettes on MCMC parameters and functions for after the model is estimated; added messages about coding of ordinal variables

Bug fixes

Bug fixes

  • remove deprecated code specifying contrast.arg that now in some cases cause error
  • fixed problem identifying non-linear functions in formula when the name of another variable contains the function name
# JointAI 0.3.2
## Bug fixes * lme_imp(): fixed error in JAGS model when interaction between random slope variable and longitudinal variable
## Minor changes * unused levels of factors are dropped

Bug fixes

  • plot_all() uses correct level-2 %NA in title
  • simWide: case with no observed bmi values removed
  • traceplot(), densplot(): ncol and nrow now work with use_ggplot = TRUE
  • traceplot(), densplot(): error in specification of nrow fixed
  • densplot(): use of color fixed
  • functions with argument subset now return random effects covariance matrix correctly
  • summary() displays output with row name when only one node is returned and fixed display of D matrix
  • GR_crit(): Literature reference corrected
  • predict(): prediction with varying factor fixed
  • no scaling for variables involved in a function to avoid problems with re-scaling

Minor changes

  • plot_all() uses xpd = TRUE when printing text for character variables
  • list_impmodels() uses line break when output of predictor variables exceeds getOption("width")
  • summary() now displays tail-probabilities for off-diagonal elements of D
  • added option to show/hide constant effects of auxiliary variables in plots
  • predict(): now also returns newdata extended with prediction
# JointAI 0.3.0
## Bug fixes * monitor_params is now checked to avoid problems when only part of the main parameters is selected * categorical imputation models now use min-max trick to prevent probabilities outside [0, 1] * initial value generation for logistic analysis model fixed * bug-fix in re-ordering columns when a function is part of the linear predictor * bug-fix in initial values for categorical covariates * bug-fix in finding imputation method when function of variable is specified as auxiliary variable
## Minor changes * md.pattern() now uses ggplot, which scales better than the previous version * lm_imp(), glm_imp() and lme_imp() now ask about overwriting a model file * analysis_main = T stays selected when other parameters are followed as well * get_MIdat(): argument include added to select if original data are included and id variable .id is added to the dataset * subset argument uses same logit as monitor_params argument * added switch to hide messages; distinction between messages and warnings * lm_imp(), glm_imp() and lme_imp() now take argument trunc in order to truncate the distribution of incomplete variables * summary() now omits auxiliary variables from the output * imp_par_list is now returned from JointAI models * cat_vars is no longer returned from lm_imp(), glm_imp() and lme_imp(), because it is contained in Mlist$refs
## Extensions * plot_all() function added * densplot() and traceplot() optional with ggplot * densplot() option to combine chains before plotting * example datasets NHANES, simLong and simWide added * list_impmodels to print information on the imputation models and hyper-parameters * parameters() added to display the parameters to be/that were monitored * set_refcat() added to guide specification of reference categories * extension of possible functions of variables in model formula to (almost all) functions that are available in JAGS * added vignettes Minimal Example, Visualizing Incomplete Data, Parameter Selection and Model Specification

Bug fixes

  • md_pattern(): does not generate duplicate plot any more
  • corrected names of imputation methods in help file
  • scaling when no continuous covariates are in the model or scaling is deselected fixed
  • initial value specification for coefficient for auxiliary variables fixed
  • get_MIdat(): imputed values are now filled in in the correct order
  • get_MIdat(): variables imputed with lognorm are now included when extracting an imputed dataset
  • get_MIdat(): imputed values of transformed variables are now included in imputed datasets
  • problem with non valid names of factor labels fixed
  • data matrix is now ordered according to order in user-specified meth argument

Minor changes

  • md.pattern(): adaptation to new version of md.pattern() from the mice package
  • internally change all NaN to NA
  • allow for scaling of incomplete covariates with quadratic effects
  • changed hyperparameter for precision in models with logit link from 4/9 to 0.001

Extensions

  • gamma and beta imputation methods implemented